Field of the Invention
The present invention relates to a semiconductor device.
Description of the Background Art
Electronization of motor vehicles as represented by hybrid electric vehicles (HEVs) or electric vehicles (EVs) has advanced recently. Power semiconductor modules have been used for conversion of electric power of these hybrid electric vehicles or electric vehicles.
As one of such power semiconductor modules, there has been known a power semiconductor module in which at least one power semiconductor element (semiconductor chip) is fixed to a circuit plate of an insulating substrate and built in a plastic housing. For example, the plastic housing is made of a PPS resin (polyphenylene sulfide resin). The plastic housing has a hollow shape and a conductive member connecting to the outside is provided integrally with the plastic housing by insert molding. The conductive member is electrically connected to an electrode on the semiconductor chip or the circuit plate of the insulating substrate inside the plastic housing through a wiring member such as a bonding wire. The insulating substrate, the semiconductor chip and the wiring member inside the plastic housing are sealed by a sealing material made of a thermosetting resin. The sealing material made of an epoxy resin etc. serves for protecting and insulating the semiconductor chip, the bonding wire, etc. received in the plastic housing.
However, due to the kind of the resin of the plastic housing, the sealing material made of the thermosetting resin has a poor adhesion property to a resin portion of the plastic housing and a difference in linear expansion coefficient between the resin portion of the plastic housing and the sealing material is large. Accordingly, thermal stress may occur between the plastic housing and the sealing material due to repetition of generation of heat when the semiconductor chip is operated or due to the change of the ambient temperature. As a result, there is a possibility that the sealing material and the resin portion of the plastic housing may be separated in the interface therebetween. There is also a possibility that the progress of the separation between the sealing material and the resin portion of the plastic housing may affect the joining state of the bonding wire or the electrical insulation property of an internal circuit.
There is a semiconductor module in which corners in the fringe of a metal plate of an insulating substrate are curved in order to improve adhesive force between the metal plate and a mold resin (Patent Literature 1). In addition, there is a semiconductor package in which protrusions each being shaped like a quadrangular truncated pyramid are formed in at least a portion of a lead frame in order to improve the adhesion property between a sealing resin and leads (Patent Literature 2). Further, there is a package for a semiconductor light-emitting device in which a scratch index of a resin molded article is set to be not larger than a predetermined numerical value in order to suppress separation between the resin molded article for the package and a sealing material (Patent Literature 3).